Nano-sized plastics originate from direct release of nanoparticles or from degradation of discarded plastic and mainly enter the aquatic food chain through uptake by algae or herbivorous invertebrates, and then continue up the food web.

Providing quantitative information on the sources of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in urban regions is vital to establish effective abatement strategies for air pollution in a megacity.